firebird-emu: support darwin

firebird-emu supports darwin, but the derivation has not been tested on macOS.

This commit adds darwin support to the derivation, with the necessary tweaks to support building for a darwin target.
Namely, adds a workaround for NixOS#19098, and adds a missing dependency, qtquickcontrols.

Also, adds a postInstall hook which moves the MacOS .app file to the Applications/ folder in the
store, enabling proper linking to /Applications or ~/Applications and appearance in Spotlight
and Launchpad.

pkgs/applications/emulators/firebird-emu/default.nix

@@ -1,6 +1,13 @@
-{ mkDerivation, lib, fetchFromGitHub, qmake, qtbase, qtdeclarative }:
-
-mkDerivation rec {
+{ stdenv
+, lib
+, fetchFromGitHub
+, qmake
+, qtbase
+, qtdeclarative
+, qtquickcontrols
+, wrapQtAppsHook
+}:
+stdenv.mkDerivation rec {
   pname = "firebird-emu";
   version = "1.6";
 
@@ -12,16 +19,23 @@ mkDerivation rec {
     hash = "sha256-ZptjlnOiF+hKuKYvBFJL95H5YQuR99d4biOco/MVEmE=";
   };
 
-  nativeBuildInputs = [ qmake ];
+  # work around https://github.com/NixOS/nixpkgs/issues/19098
+  env.NIX_CFLAGS_COMPILE = lib.optionalString (stdenv.cc.isClang && stdenv.isDarwin) "-fno-lto";
+
+  nativeBuildInputs = [ wrapQtAppsHook qmake ];
+
+  buildInputs = [ qtbase qtdeclarative qtquickcontrols ];
 
-  buildInputs = [ qtbase qtdeclarative ];
+  postInstall = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    mkdir $out/Applications
+    mv $out/bin/${pname}.app $out/Applications/
+  '';
 
   meta = {
     homepage = "https://github.com/nspire-emus/firebird";
     description = "Third-party multi-platform emulator of the ARM-based TI-Nspire™ calculators";
     license = lib.licenses.gpl3;
     maintainers = with lib.maintainers; [ pneumaticat ];
-    # Only tested on Linux, but likely possible to build on, e.g. macOS
-    platforms = lib.platforms.linux;
+    platforms = lib.platforms.unix;
   };
 }